Resected tumor sample was collected from a 46-year-old male patient and transported in DMEM (GIBCO) on ice immediately after surgical. Tumor pieces were digested with accumax to obtain single cell suspension. Single cells were picked up and lysed with 200 ng carrier RNA mixture (containing 100 ng 5’-phosphorylated small carrier RNA mimic). The poly-A RNAs were selected using a NEBNext Poly(A) mRNA Magnetic Isolation Module (NEB #E7490), and the small RNAs remained in the supernatant after poly-A selection. The poly(A) mRNA sequencing library was constructed following the manufacturer’s protocol using a NEBNext kit (NEB #E7530). After adaptor ligation and USER digestion, cDNA fragments from the RNA carrier were removed by Not I digestion. After Not I digestion, the library DNA was purified for PCR amplification.